Plasma Source For Rotating Susceptor

ABSTRACT

Plasma source assemblies comprising an RF hot electrode having a body and at least one return electrode spaced from the RF hot electrode to provide a gap in which a plasma can be formed. An RF feed is connected to the RF hot electrode at a distance from the inner peripheral end of the RF hot electrode that is less than or equal to about 25% of the length of the RF hot electrode.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.62/506,570, filed May 15, 2017, the entire disclosure of which is herebyincorporated by reference herein.

FIELD

Embodiments of the disclosure generally relate to an apparatus forprocessing substrates. More particularly, embodiments of the disclosurerelate to modular plasma sources for use with processing chambers likebatch processors.

BACKGROUND

Semiconductor device formation is commonly conducted in substrateprocessing platforms containing multiple chambers. In some instances,the purpose of a multi-chamber processing platform or cluster tool is toperform two or more processes on a substrate sequentially in acontrolled environment. In other instances, however, a multiple chamberprocessing platform may only perform a single processing step onsubstrates; the additional chambers are intended to maximize the rate atwhich substrates are processed by the platform. In the latter case, theprocess performed on substrates is typically a batch process, wherein arelatively large number of substrates, e.g. 25 or 50, are processed in agiven chamber simultaneously. Batch processing is especially beneficialfor processes that are too time-consuming to be performed on individualsubstrates in an economically viable manner, such as for atomic layerdeposition (ALD) processes and some chemical vapor deposition (CVD)processes.

Some ALD systems, especially spatial ALD systems with rotating substrateplatens, benefit from a modular plasma source, i.e., a source that canbe easily inserted into the system. The plasma source consists of avolume where plasma is generated, and a way to expose a workpiece to aflux of charged particles and active chemical radical species.

Thermal ALD and CVD processes frequently incorporate treatments for filmquality enhancements. These treatments typically comprise energetic orreactive species. Plasma sources are a primary source for such species.Some concerns of plasma sources include energetic bombardment throughions and contamination of materials from the plasma source due tosputtering.

For linear radial plasma sources in any system with a rotating susceptor(also called a platen), the plasma exposure (treatment) is larger at thewafer inner diameter compared to the outer diameter by a factor of about2.7. Therefore, for uniform plasma exposure, the plasma should bestronger at the outer diameter than the inner diameter. Therefore, thereis a need in the art for plasma sources that achieve uniform plasmaexposure in rotating platen processing systems.

SUMMARY

One or more embodiments of the disclosure are directed to plasma sourceassemblies comprising a housing having an inner peripheral edge, anouter peripheral edge and a front face. The housing includes a gas inletto form a flow path from the gas inlet to allow a flow of gas to passthrough the housing and out an opening in the front face. An RF hotelectrode is within the housing and has an elongate body with an innerperipheral end near the inner peripheral edge of the housing and anouter peripheral end near the outer peripheral edge of the housing anddefining a length of the RF hot electrode. A return electrode has anelongate body that extends between the inner peripheral edge and theouter peripheral edge of the housing. The return electrode is spacedfrom the RF hot electrode to provide a gap in which a plasma can form.An RF feed is connected to the RF hot electrode at a distance from theinner peripheral end of the RF hot electrode that is less or equal toabout 25% of the length of the RF hot electrode.

Additional embodiments of the disclosure are directed to processingchambers comprising a susceptor assembly and a gas distributionassembly. The susceptor assembly is within the processing chamber andhas a top surface to support and rotate a plurality of substrates arounda central axis. The gas distribution assembly has a front surface facingthe top surface of the susceptor assembly to direct a flow of gasestoward the top surface of the susceptor assembly. The gas distributionassembly includes a plasma source assembly comprising a housing with aninner peripheral edge, an outer peripheral edge and a front face. Thehousing includes a gas inlet to form a flow path from the gas inlet toallow a flow of gas to pass through the housing and out an opening inthe front face. An RF hot electrode is within the housing. The RF hotelectrode has an elongate body with a first surface and a secondsurface, an inner peripheral end near the inner peripheral edge of thehousing and an outer peripheral end near the outer peripheral edge ofthe housing and defining a length of the RF hot electrode. A firstreturn electrode is within the housing. The first return electrode hasan elongate body extending between the inner peripheral edge and theouter peripheral edge of the housing. The first return electrode isspaced from the first surface of the RF hot electrode to provide a firstgap in which a plasma can form. A second return electrode is within thehousing. The second return electrode has an elongate body extendingbetween the inner peripheral edge and the outer peripheral edge of thehousing. The second return electrode is spaced from the second surfaceof the RF hot electrode to provide a second gap in which a plasma canform. An RF feed is connected to the RF hot electrode at a distance fromthe inner peripheral end of the RF hot electrode that is less or equalto about 25% of the length of the RF hot electrode. The front face ofthe housing of the plasma source assembly is positioned a distance fromthe top surface of the susceptor assembly in the range of about 1 mm toabout 5 mm. An ion flux generated at the inner peripheral end of the RFhot electrode is less than an ion flux generated at the outer peripheralend of the RF hot electrode.

Further embodiments of the disclosure are directed to methods ofprocessing a substrate. A substrate is positioned on a susceptorassembly adjacent a gas distribution assembly. The gas distributionassembly includes a plasma source assembly comprising a housing havingan inner peripheral edge, an outer peripheral edge and a front face. Thehousing includes a gas inlet to form a flow path from the gas inlet toallow a flow of gas to pass through the housing and out an opening inthe front face. An RF hot electrode is within the housing and has anelongate body with a first surface and a second surface, an innerperipheral end near the inner peripheral edge of the housing and anouter peripheral end near the outer peripheral edge of the housing anddefining a length of the RF hot electrode. A first return electrode iswithin the housing, the first return electrode has an elongate bodyextending between the inner peripheral edge and the outer peripheraledge of the housing. The first return electrode is spaced from the firstsurface of the RF hot electrode to provide a first gap in which a plasmacan form. A second return electrode is within the housing and has anelongate body extending between the inner peripheral edge and the outerperipheral edge of the housing. The second return electrode is spacedfrom the second surface of the RF hot electrode to provide a second gapin which a plasma can form. An RF feed is connected to the RF hotelectrode at a distance from the inner peripheral end of the RF hotelectrode that is less or equal to about 25% of the length of the RF hotelectrode. A gas is flowed through the gas inlet of the housing into thefirst gap between the RF hot electrode and the first return electrodeand the second gap between the RF hot electrode and the second returnelectrode. The RF hot electrode is energized to form a plasma in thefirst gap and the second gap. The plasma has an ion flux generated atthe inner peripheral end of the RF hot electrode that is less than anion flux generated at the outer peripheral end of the RF hot electrode.The substrate is exposed to the plasma.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of embodiments ofthe disclosure can be understood in detail, a more particulardescription of embodiments of the disclosure, briefly summarized above,may be had by reference to embodiments, some of which are illustrated inthe appended drawings. It is to be noted, however, that the appendeddrawings illustrate only typical embodiments of this disclosure and aretherefore not to be considered limiting of its scope, for the disclosuremay admit to other equally effective embodiments.

FIG. 1 shows a schematic cross-sectional view of a substrate processingsystem in accordance with one or more embodiments of the disclosure;

FIG. 2 shows a perspective view of a substrate processing system inaccordance with one or more embodiment of the disclosure;

FIG. 3 shows a schematic of a substrate processing system in accordancewith one or more embodiment of the disclosure;

FIG. 4 shows a schematic view of a front of a gas distribution assemblyin accordance with one or more embodiment of the disclosure;

FIG. 5 shows a schematic view of a processing chamber in accordance withone or more embodiment of the disclosure;

FIG. 6 shows a schematic cross-sectional view of a plasma sourceassembly in accordance with one or more embodiment of the disclosure;

FIG. 7 shows a partial perspective view of a plasma source assembly inaccordance with one or more embodiments of the disclosure;

FIG. 8 shows a partial perspective view of a plasma source assembly inaccordance with one or more embodiments of the disclosure;

FIG. 9 shows a partial schematic side view of a plasma source assemblyin accordance with one or more embodiments of the disclosure;

FIGS. 10A and 10B show a schematic bottom views of plasma sourceassemblies in accordance with one or more embodiments of the disclosure;

FIG. 11 shows a schematic bottom view of a plasma source assembly withserpentine electrodes in accordance with one or more embodiments of thedisclosure;

FIG. 12 shows a schematic bottom view of a plasma source assembly inaccordance with one or more embodiments of the disclosure;

FIG. 13 shows a partial cross-sectional side schematic of plasma sourceassembly electrodes in accordance with one or more embodiment of thedisclosure;

FIG. 14 shows a partial cross-sectional side schematic of a plasmasource assembly electrodes in accordance with one or more embodiments ofthe disclosure;

FIG. 15 shows a partial view of a plasma source assembly in accordancewith one or more embodiments of the disclosure;

FIG. 16 shows a side view of a plasma source assembly in accordance withone or more embodiments of the disclosure;

FIG. 17 shows a cross-sectional view of a plasma source assembly inaccordance with one or more embodiments of the disclosure; and

FIG. 18 shows a graph of the plasma flux as a function of radiallocation on the wafer using a plasma source assembly in accordance withone or more embodiment of the disclosure.

DETAILED DESCRIPTION

Embodiments of the disclosure provide a substrate processing system forcontinuous substrate deposition to maximize throughput and improveprocessing efficiency. The substrate processing system can also be usedfor pre-deposition and post-deposition plasma treatments.

As used in this specification and the appended claims, the term“substrate” and “wafer” are used interchangeably, both referring to asurface, or portion of a surface, upon which a process acts. It willalso be understood by those skilled in the art that reference to asubstrate can also refer to only a portion of the substrate, unless thecontext clearly indicates otherwise. Additionally, reference todepositing on a substrate can mean both a bare substrate and a substratewith one or more films or features deposited or formed thereon.

As used in this specification and the appended claims, the terms“reactive gas”, “precursor”, “reactant”, and the like, are usedinterchangeably to mean a gas that includes a species which is reactivewith a substrate surface. For example, a first “reactive gas” may simplyadsorb onto the surface of a substrate and be available for furtherchemical reaction with a second reactive gas.

As used in this specification and the appended claims, the term “reducedpressure” means a pressure less than about 100 Torr, or less than about75 Torr, or less than about 50 Torr, or less than about 25 Torr. Forexample, “medium pressure” defined as in the range of about 1 Torr toabout 25 Torr is reduced pressure.

Rotating platen chambers are being considered for many applications. Insuch a chamber, one or more wafers are placed on a rotating holder(“platen”). As the platen rotates, the wafers move between variousprocessing areas. For example, in ALD, the processing areas would exposethe wafer to precursors and reactants. In addition, plasma exposure maybe used as a reactant or to treat the film or the substrate surface forenhanced film growth or to modify film properties. Some embodiments ofthe disclosure provide for uniform deposition and post-treatment (e.g.,densification) of ALD films when using a rotating platen ALD chamber.

Rotating platen ALD chambers can deposit films by traditionaltime-domain processes where the entire wafer is exposed to a first gas,purged and then exposed to the second gas, or by spatial ALD whereportions of the wafer are exposed to the first gas and portions areexposed to the second gas and the movement of the wafer through thesegas streams deposits the layer.

As used in this specification and the appended claims, the terms“pie-shaped” and “wedge-shaped” are used interchangeably to describe abody that is a generally circular sector. For example, a wedge-shapedsegment may be a fraction of a circle or disc-shaped structure. Theinner edge of the pie-shaped segment can come to a point or can betruncated to a flat edge or rounded. The path of the substrates can beperpendicular to the gas ports. In some embodiments, each of the gasinjector assemblies comprises a plurality of elongate gas ports whichextend in a direction substantially perpendicular to the path traversedby a substrate, where a front edge of the gas ports is substantiallyparallel to the platen. As used in this specification and the appendedclaims, the term “substantially perpendicular” means that the generaldirection of movement of the substrates is along a plane approximatelyperpendicular (e.g., about 45° to 90°) to the axis of the gas ports. Fora wedge-shaped gas port, the axis of the gas port can be considered tobe a line defined as the mid-point of the width of the port extendingalong the length of the port.

FIG. 1 shows a cross-section of a processing chamber 100 including a gasdistribution assembly 120, also referred to as injectors or an injectorassembly, and a susceptor assembly 140. The gas distribution assembly120 is any type of gas delivery device used in a processing chamber. Thegas distribution assembly 120 includes a front surface 121 which facesthe susceptor assembly 140. The front surface 121 can have any number orvariety of openings to deliver a flow of gases toward the susceptorassembly 140. The gas distribution assembly 120 also includes an outerperipheral edge 124 which in the embodiments shown, is substantiallyround.

The specific type of gas distribution assembly 120 used can varydepending on the particular process being used. Embodiments of thedisclosure can be used with any type of processing system where the gapbetween the susceptor and the gas distribution assembly is controlled.While various types of gas distribution assemblies can be employed(e.g., showerheads), embodiments of the disclosure may be particularlyuseful with spatial ALD gas distribution assemblies which have aplurality of substantially parallel gas channels. As used in thisspecification and the appended claims, the term “substantially parallel”means that the elongate axis of the gas channels extend in the samegeneral direction. There can be slight imperfections in the parallelismof the gas channels. The plurality of substantially parallel gaschannels can include at least one first reactive gas A channel, at leastone second reactive gas B channel, at least one purge gas P channeland/or at least one vacuum V channel. The gases flowing from the firstreactive gas A channel(s), the second reactive gas B channel(s) and thepurge gas P channel(s) are directed toward the top surface of the wafer.Some of the gas flow moves horizontally across the surface of the waferand out of the processing region through the purge gas P channel(s). Asubstrate moving from one end of the gas distribution assembly to theother end will be exposed to each of the process gases in turn, forminga layer on the substrate surface.

In some embodiments, the gas distribution assembly 120 is a rigidstationary body made of a single injector unit. In one or moreembodiments, the gas distribution assembly 120 is made up of a pluralityof individual sectors (e.g., injector units 122), as shown in FIG. 2.Either a single piece body or a multi-sector body can be used with thevarious embodiments of the disclosure described.

The susceptor assembly 140 is positioned beneath the gas distributionassembly 120. The susceptor assembly 140 includes a top surface 141 andat least one recess 142 in the top surface 141. The susceptor assembly140 also has a bottom surface 143 and an edge 144. The recess 142 can beany suitable shape and size depending on the shape and size of thesubstrates 60 being processed. In the embodiment shown in FIG. 1, therecess 142 has a flat bottom to support the bottom of the wafer;however, the bottom of the recess can vary. In some embodiments, therecess has step regions around the outer peripheral edge of the recesswhich are sized to support the outer peripheral edge of the wafer. Theamount of the outer peripheral edge of the wafer that is supported bythe steps can vary depending on, for example, the thickness of the waferand the presence of features already present on the back side of thewafer.

In some embodiments, as shown in FIG. 1, the recess 142 in the topsurface 141 of the susceptor assembly 140 is sized so that a substrate60 supported in the recess 142 has a top surface 61 substantiallycoplanar with the top surface 141 of the susceptor 140. As used in thisspecification and the appended claims, the term “substantially coplanar”means that the top surface of the wafer and the top surface of thesusceptor assembly are coplanar within ±0.2 mm. In some embodiments, thetop surfaces are coplanar within ±0.15 mm, ±0.10 mm or ±0.05 mm. Therecess 142 of some embodiments supports a wafer so that the innerdiameter (ID) of the wafer is located within the range of about 170 mmto about 185 mm from the center (axis of rotation) of the susceptor. Insome embodiments, the recess 142 supports a wafer so that the outerdiameter (OD) of the wafer is located in the range of about 470 mm toabout 485 mm from the center (axis of rotation) of the susceptor.

The susceptor assembly 140 of FIG. 1 includes a support post 160 whichis capable of lifting, lowering and rotating the susceptor assembly 140.The susceptor assembly may include a heater, or gas lines, or electricalcomponents within the center of the support post 160. The support post160 may be the primary means of increasing or decreasing the gap betweenthe susceptor assembly 140 and the gas distribution assembly 120, movingthe susceptor assembly 140 into proper position. The susceptor assembly140 may also include fine tuning actuators 162 which can makemicro-adjustments to susceptor assembly 140 to create a predeterminedgap 170 between the susceptor assembly 140 and the gas distributionassembly 120. In some embodiments, the gap 170 distance is in the rangeof about 0.1 mm to about 5.0 mm, or in the range of about 0.1 mm toabout 3.0 mm, or in the range of about 0.1 mm to about 2.0 mm, or in therange of about 0.2 mm to about 1.8 mm, or in the range of about 0.3 mmto about 1.7 mm, or in the range of about 0.4 mm to about 1.6 mm, or inthe range of about 0.5 mm to about 1.5 mm, or in the range of about 0.6mm to about 1.4 mm, or in the range of about 0.7 mm to about 1.3 mm, orin the range of about 0.8 mm to about 1.2 mm, or in the range of about0.9 mm to about 1.1 mm, or about 1 mm.

The processing chamber 100 shown in the Figures is a carousel-typechamber in which the susceptor assembly 140 can hold a plurality ofsubstrates 60. As shown in FIG. 2, the gas distribution assembly 120 mayinclude a plurality of separate injector units 122, each injector unit122 being capable of depositing a film on the wafer, as the wafer ismoved beneath the injector unit. Two pie-shaped injector units 122 areshown positioned on approximately opposite sides of and above thesusceptor assembly 140. This number of injector units 122 is shown forillustrative purposes only. It will be understood that more or lessinjector units 122 can be included. In some embodiments, there are asufficient number of pie-shaped injector units 122 to form a shapeconforming to the shape of the susceptor assembly 140. In someembodiments, each of the individual pie-shaped injector units 122 may beindependently moved, removed and/or replaced without affecting any ofthe other injector units 122. For example, one segment may be raised topermit a robot to access the region between the susceptor assembly 140and gas distribution assembly 120 to load/unload substrates 60.

Processing chambers having multiple gas injectors can be used to processmultiple wafers simultaneously so that the wafers experience the sameprocess flow. For example, as shown in FIG. 3, the processing chamber100 has four gas injector assemblies and four substrates 60. At theoutset of processing, the substrates 60 can be positioned between theinjector assemblies 30. Rotating 17 the susceptor assembly 140 by 45°will result in each substrate 60 which is between gas distributionassemblies 120 to be moved to an gas distribution assembly 120 for filmdeposition, as illustrated by the dotted circle under the gasdistribution assemblies 120. An additional 45° rotation would move thesubstrates 60 away from the injector assemblies 30. With spatial ALDinjectors, a film is deposited on the wafer during movement of the waferrelative to the injector assembly. In some embodiments, the susceptorassembly 140 is rotated in increments that prevent the substrates 60from stopping beneath the gas distribution assemblies 120. The number ofsubstrates 60 and gas distribution assemblies 120 can be the same ordifferent. In some embodiments, there is the same number of wafers beingprocessed as there are gas distribution assemblies. In one or moreembodiments, the number of wafers being processed are fraction of or aninteger multiple of the number of gas distribution assemblies. Forexample, if there are four gas distribution assemblies, there are 4xwafers being processed, where x is an integer value greater than orequal to one.

The processing chamber 100 shown in FIG. 3 is merely representative ofone possible configuration and should not be taken as limiting the scopeof the disclosure. Here, the processing chamber 100 includes a pluralityof gas distribution assemblies 120. In the embodiment shown, there arefour gas distribution assemblies (also called injector assemblies 30)evenly spaced about the processing chamber 100. The processing chamber100 shown is octagonal, however, those skilled in the art willunderstand that this is one possible shape and should not be taken aslimiting the scope of the disclosure. The gas distribution assemblies120 shown are trapezoidal, but can be a single circular component ormade up of a plurality of pie-shaped segments, like that shown in FIG.2.

The embodiment shown in FIG. 3 includes a load lock chamber 180, or anauxiliary chamber like a buffer station. This chamber 180 is connectedto a side of the processing chamber 100 to allow, for example thesubstrates (also referred to as substrates 60) to be loaded/unloadedfrom the processing chamber 100. A wafer robot may be positioned in thechamber 180 to move the substrate onto the susceptor.

Rotation of the carousel (e.g., the susceptor assembly 140) can becontinuous or discontinuous. In continuous processing, the wafers areconstantly rotating so that they are exposed to each of the injectors inturn. In discontinuous processing, the wafers can be moved to theinjector region and stopped, and then to the region 84 between theinjectors and stopped. For example, the carousel can rotate so that thewafers move from an inter-injector region across the injector (or stopadjacent the injector) and on to the next inter-injector region wherethe carousel can pause again. Pausing between the injectors may providetime for additional processing steps between each layer deposition(e.g., exposure to plasma).

FIG. 4 shows a sector or portion of a gas distribution assembly 220,which may be referred to as an injector unit 122. The injector units 122can be used individually or in combination with other injector units.For example, as shown in FIG. 5, four of the injector units 122 of FIG.4 are combined to form a single gas distribution assembly 220. (Thelines separating the four injector units are not shown for clarity.)While the injector unit 122 of FIG. 4 has both a first reactive gas port125 and a second reactive gas port 135 in addition to purge gas ports155 and vacuum ports 145, an injector unit 122 does not need all ofthese components.

Referring to both FIGS. 4 and 5, a gas distribution assembly 220 inaccordance with one or more embodiment may comprise a plurality ofsectors (or injector units 122) with each sector being identical ordifferent. The gas distribution assembly 220 is positioned within theprocessing chamber and comprises a plurality of elongate gas ports 125,135, 155 and vacuum ports 145 in a front surface 121 of the gasdistribution assembly 220. The plurality of elongate gas ports 125, 135,vacuum ports 145 (surrounding gas ports 125, 135) and purge gas ports155 extend from an area adjacent the inner peripheral edge 123 toward anarea adjacent the outer peripheral edge 124 of the gas distributionassembly 220. The plurality of gas ports shown include a first reactivegas port 125, a second reactive gas port 135, a vacuum port 145 whichsurrounds each of the first reactive gas ports and the second reactivegas ports and a purge gas port 155.

With reference to the embodiments shown in FIG. 4 or 5, when statingthat the ports extend from at least about an inner peripheral region toat least about an outer peripheral region, however, the ports can extendmore than just radially from inner to outer regions. The ports canextend tangentially as vacuum port 145 surrounds reactive gas port 125and reactive gas port 135. In the embodiment shown in FIGS. 4 and 5, thewedge shaped reactive gas ports 125, 135 are surrounded on all edges,including adjacent the inner peripheral region and outer peripheralregion, by a vacuum port 145.

Referring to FIG. 4, as a substrate moves along path 127, each portionof the substrate surface is exposed to the various reactive gases. Tofollow the path 127, the substrate will be exposed to, or “see”, a purgegas port 155, a vacuum port 145, a first reactive gas port 125, a vacuumport 145, a purge gas port 155, a vacuum port 145, a second reactive gasport 135 and a vacuum port 145. Thus, at the end of the path 127 shownin FIG. 4, the substrate has been exposed to gas streams from the firstreactive gas port 125 and the second reactive gas port 135 to form alayer. The injector unit 122 shown makes a quarter circle but could belarger or smaller. The gas distribution assembly 220 shown in FIG. 5 canbe considered a combination of four of the injector units 122 of FIG. 4connected in series.

The injector unit 122 of FIG. 4 shows a gas curtain 150 that separatesthe reactive gases. The term “gas curtain” is used to describe anycombination of gas flows or vacuum that separate reactive gases frommixing. The gas curtain 150 shown in FIG. 4 comprises the portion of thevacuum port 145 next to the first reactive gas port 125, the purge gasport 155 in the middle and a portion of the vacuum port 145 next to thesecond reactive gas port 135. This combination of gas flow and vacuumcan be used to prevent or minimize gas phase reactions of the firstreactive gas and the second reactive gas.

Referring to FIG. 5, the combination of gas flows and vacuum from thegas distribution assembly 220 form a separation into a plurality ofprocessing regions 250. The processing regions are roughly definedaround the individual reactive gas ports 125, 135 with the gas curtain150 between 250. The embodiment shown in FIG. 5 makes up eight separateprocessing regions 250 with eight separate gas curtains 150 between. Aprocessing chamber can have at least two processing region. In someembodiments, there are at least three, four, five, six, seven, eight,nine, 10, 11 or 12 processing regions.

During processing a substrate may be exposed to more than one processingregion 250 at any given time. However, the portions that are exposed tothe different processing regions will have a gas curtain separating thetwo. For example, if the leading edge of a substrate enters a processingregion including the second reactive gas port 135, a middle portion ofthe substrate will be under a gas curtain 150 and the trailing edge ofthe substrate will be in a processing region including the firstreactive gas port 125.

A factory interface 280, which can be, for example, a load lock chamber,is shown connected to the processing chamber 100. A substrate 60 isshown superimposed over the gas distribution assembly 220 to provide aframe of reference. The substrate 60 may often sit on a susceptorassembly to be held near the front surface 121 of the gas distributionassembly 120 (also referred to as a gas distribution plate). Thesubstrate 60 is loaded via the factory interface 280 into the processingchamber 100 onto a substrate support or susceptor assembly (see FIG. 3).The substrate 60 can be shown positioned within a processing regionbecause the substrate is located adjacent the first reactive gas port125 and between two gas curtains 150 a, 150 b. Rotating the substrate 60along path 127 will move the substrate counter-clockwise around theprocessing chamber 100. Thus, the substrate 60 will be exposed to thefirst processing region 250 a through the eighth processing region 250h, including all processing regions between. For each cycle around theprocessing chamber, using the gas distribution assembly shown, thesubstrate 60 will be exposed to four ALD cycles of first reactive gasand second reactive gas.

The conventional ALD sequence in a batch processor, like that of FIG. 5,maintains chemical A and B flow respectively from spatially separatedinjectors with pump/purge section between. The conventional ALD sequencehas a starting and ending pattern which might result in non-uniformityof the deposited film. The inventors have surprisingly discovered that atime based ALD process performed in a spatial ALD batch processingchamber provides a film with higher uniformity. The basic process ofexposure to gas A, no reactive gas, gas B, no reactive gas would be tosweep the substrate under the injectors to saturate the surface withchemical A and B respectively to avoid having a starting and endingpattern form in the film. The inventors have surprisingly found that thetime based approach is especially beneficial when the target filmthickness is thin (e.g., less than 20 ALD cycles), where starting andending pattern have a significant impact on the within wafer uniformityperformance. The inventors have also discovered that the reactionprocess to create SiCN, SiCO and SiCON films, as described herein, couldnot be accomplished with a time-domain process. The amount of time usedto purge the processing chamber results in the stripping of materialfrom the substrate surface. The stripping does not happen with thespatial ALD process described because the time under the gas curtain isshort.

Accordingly, embodiments of the disclosure are directed to processingmethods comprising a processing chamber 100 with a plurality ofprocessing regions 250 a-250 h with each processing region separatedfrom an adjacent region by a gas curtain 150. For example, theprocessing chamber shown in FIG. 5. The number of gas curtains andprocessing regions within the processing chamber can be any suitablenumber depending on the arrangement of gas flows. The embodiment shownin FIG. 5 has eight gas curtains 150 and eight processing regions 250a-250 h. The number of gas curtains is generally equal to or greaterthan the number of processing regions. For example, if region 250 a hadno reactive gas flow, but merely served as a loading area, theprocessing chamber would have seven processing regions and eight gascurtains.

A plurality of substrates 60 are positioned on a substrate support, forexample, the susceptor assembly 140 shown FIGS. 1 and 2. The pluralityof substrates 60 are rotated around the processing regions forprocessing. Generally, the gas curtains 150 are engaged (gas flowing andvacuum on) throughout processing including periods when no reactive gasis flowing into the chamber.

A first reactive gas A is flowed into one or more of the processingregions 250 while an inert gas is flowed into any processing region 250which does not have a first reactive gas A flowing into it. For exampleif the first reactive gas is flowing into processing regions 250 bthrough processing region 250 h, an inert gas would be flowing intoprocessing region 250 a. The inert gas can be flowed through the firstreactive gas port 125 or the second reactive gas port 135.

The inert gas flow within the processing regions can be constant orvaried. In some embodiments, the reactive gas is co-flowed with an inertgas. The inert gas will act as a carrier and diluent. Since the amountof reactive gas, relative to the carrier gas, is small, co-flowing maymake balancing the gas pressures between the processing regions easierby decreasing the differences in pressure between adjacent regions.

Some embodiments of the disclosure are directed to injector modules.While the injector modules are described with respect to a spatial ALDprocessing chamber, those skilled in the art will understand that themodules are not limited to spatial ALD chambers and can be applicable toany injector situation where increasing gas flow uniformity is useful.

Some embodiments of the disclosure advantageously provide modular plasmasource assemblies, i.e., a source that can be easily inserted into andremoved from the processing system. Such a source may have all or mostof its hardware operating at the same pressure level as the atomic layerdeposition process, typically 1-50 Torr. Some embodiments of thedisclosure provide plasma sources with improved ion flux across thewafer surface. In some embodiments, plasma sources include a capacitivesource between three plates aligned substantially perpendicular to thewafer surface. In some embodiments, the outer plates are grounded andthe inner plate is powered. A plasma can be created between the plateswhile the gas species flows between the plates toward the wafer surface.The plasma is substantially confined to the source and minimizessputtered material from the powered plate reaching the wafer surface.Some embodiments of the disclosure advantageously provide a plasmasource that minimizes or eliminates contamination of the substrate bymaterial sputtered from the hot electrode. Some embodiments alsoadvantageously provide a soft plasma that does not substantially changeof the substrate surface. One or more embodiments provide an apparatusthat can generate a plasma without allowing the electrical return pathto go through the substrate. Some embodiments of the disclosure providemodular remote plasma sources that can be added to or removed from a gasdistribution assembly. The remote plasma source generates a plasmawithout using the substrate or substrate support as an electrode.

The gap between the RF hot electrode (the powered electrode) and theground plate (referred to as a return electrode) can be varied. In someembodiments, the gap is in the range of about 4 mm to about 15 mm andmay be adjustable. The width of the RF hot electrode can be varied. Forexample, the plates can be tapered to accelerate ions. In use, thegaseous species flowing in the gap between the RF hot electrode and thereturn electrode become ionized. The ionized species can then contactthe substrate surface. The plasma formed by the various embodiments is asoft plasma that does not substantially change the substrate surface.

Referring to FIGS. 6 through 17, one or more embodiments of thedisclosure are directed to modular capacitively coupled plasma sources300. As used in this specification and the appended claims, the term“modular” means that plasma source 300 can be attached to or removedfrom a processing chamber. A modular source can generally be moved,removed or attached by a single person.

FIG. 6 shows a cross-section of a plasma source assembly 300 inaccordance with one or more embodiment of the disclosure. The plasmasource assembly 300 shown in FIG. 6 includes a housing 310 with a gasinlet 315 and a front face 312. The gas inlet 315 allows a flow of gasto move along the flow path 318 through the housing 310 and out anopening 313 in the front face 312. The embodiment shown has a gas inlet315 illustrated off-center for descriptive purposes, but those skilledin the art will understand that the gas inlet 315 can be centered in thehousing 310. Additionally, some embodiments include a plenum 316 toincrease the uniformity of the gas flow through the flow path 318. Theplenum 316 of some embodiments is at least partially filled with adielectric, which has a plurality of through holes and/or plenums toallow gas to reach the plasma cavity (gap 340, 340 b) uniformly. Thethrough holes and/or plenums have dimensions small enough to preventplasma breakdown. In some embodiments, the through holes have diametersless than or equal to about 1 mm, 0.95 mm, 0.9 mm, 0.85 mm, 0.8 mm, 0.75mm, 0.7 mm, 0.65 mm or 0.6 mm.

The plasma source assembly 300 includes an RF hot electrode 320 and atleast one return electrode 330. The return electrode 330 is anyconductive material that forms a complete circuit with the RF hotelectrode 320. Those skilled in the art will understand that the returnelectrode 330 can provide a pathway for electrons to flow. The term“return” used in this manner means that the electrode is part of theelectrical pathway of the plasma components and does not imply adirection for the flow of current or electrons.

Referring to FIGS. 6 to 8, the RF hot electrode 320 has a first surface322 and a second surface 324 opposite the first surface 322. FIG. 6shows a cross-section of a plasma source assembly 300 while FIGS. 7 and8 show partial perspective views of the electrodes. As used in thisregard, the first surface 322 and second surface 324 are on oppositesides of the thickness T of the RF hot electrode 320. The RF hotelectrode 320 is a generally shaped as a rectangular prism with a heightH, thickness T and length L. The RF hot electrode 320 has a firstsurface 322 oriented substantially parallel to the flow path 318. Asused in this regard, the term “substantially parallel” means that thesurface is within ±10° of parallel (defined as 0°).

The return electrode 330 is similarly shaped to the RF hot electrode320. The return electrode has a first surface 332 that is orientedsubstantially parallel to the flow path 318. The first surface 332 ofthe return electrode 330 is spaced from the first surface 322 of the RFhot electrode 320 to form a gap 340.

The return electrode 330,330 b can be any suitable material including,but not limited to, aluminum, stainless steel and copper. The returnelectrode 330, 330 b can have any suitable electrical characteristics.In some embodiments, the return electrode 330, 330 b is a groundelectrode. A ground electrode is any conductive material in electricalcontact with electrical ground.

In some embodiments, the return electrode 330, 330 b is a poweredelectrode different from the RF hot electrode 320. As used in thismanner, “different from the RF hot electrode” means that the electricalproperties or potential are different from the RF hot electrode. Forexample, the driving power of the generated plasma may be tuned in apush-pull manner from a single source using a phase shifter to minimizeinteraction with the wafer. In embodiments of this sort, the RF hotelectrode 320 may be, for example, 180° out of phase with the returnelectrode 330.

As shown in FIG. 7, some embodiments of the plasma source assemblyfurther comprise a second return electrode 330 b. The second returnelectrode 330 b has a first surface 332 b which is orientedsubstantially parallel to the flow path 318. The first surface 332 b ofthe second return electrode 330 b is spaced from a second surface 324 ofthe RF hot electrode 320 to form a gap 340 b. The gap 340 and gap 340 bcan have the same or different dimensions. In some embodiments, the gap340, 340 b between the RF hot electrode 320 and the return electrode330, 330 b is in the range of about 4 mm to about 15 mm, or in the rangeof about 5 mm to about 14 mm, or in the range of about 7 mm to about 13mm, or in the range of about 9 mm to about 12 mm, or about 11 mm.

Referring to FIG. 9, in some embodiments the gap 340, 340 b between theRF hot electrode 320 and the return electrode 330, 330 b changes alongthe height H of the electrodes. In the embodiment shown, the thickness Tis greater adjacent the gas inlet 315 than adjacent the front face 312.Stated different the size of the gap 340, 340 b is smaller adjacent thegas inlet 315 than adjacent the front face 312. Without being bound byany particular theory of operation, it is believed that the taperedthickness of the RF hot electrode 320 may cause ions to the acceleratedtowards the wafer.

The thickness T of the RF hot electrode 320 can be any suitablethickness depending on, for example, the electrode material. In someembodiments, the RF hot electrode has a thickness in the range of about3 mm to about 11 mm, or in the range of about 4 mm to about 10 mm, or inthe range of about 6 mm to about 9 mm or about 8 mm.

The height H of the RF hot electrode 320 can be varied. In someembodiments, the height H of the RF hot electrode 320 is in the range ofabout 8 mm to about 40 mm, or in the range of about 9 mm to about 35 mm,or in the range of about 10 mm to about 30 mm, or in the range of about11 mm to about 25 mm, or in the range of about 12 mm to about 20 mm, orin the range of about 13 mm to about 15 mm or about 14 mm.

In some embodiments, the housing 310 of the plasma source assembly 300is wedge-shaped. FIGS. 10A and 10B show two embodiments incorporatingwedge-shaped housings 310. In FIG. 10A, the RF hot electrode 320 and thereturn electrode 330 extend along a major axis 308 of the housing 310.The major axis 308, as used in this manner, refers to the axis betweenthe middle of the inner peripheral edge 123 and the outer peripheraledge 124 of the housing 310. In FIG. 10B, the RF hot electrodes 320 andthe return electrodes 330 extend perpendicular to the major axis 308 ofthe housing 310.

The spacing between the RF hot electrodes 320 and the return electrodes330 can be substantially the same throughout the plasma source assemblyor can vary. For example, in some embodiments, the RF hot electrode andthe return electrode are spaced further apart at the outer peripheraledge 124 of the wedge-shaped housing 310 than near the inner peripheraledge 123.

FIG. 11 shows another embodiment of the disclosure in which the RF hotelectrode 320 has a serpentine shape within the housing 310. As used inthis regard, the term “serpentine shape” means that the electrode has awinding shape. The shape can conform to the shape of the housing 310.For example, the housing 310 of FIG. 11 is wedge-shaped and the RF hotelectrode 320 has a serpentine shape that is larger near the outerperipheral edge 124 than near the inner peripheral edge 123. The returnelectrode 330 has a complementary shape to the RF hot electrode 320 tomaintain substantially the same gap 340 along the length of theserpentine shape. As used in this regard, the term “substantially thesame gap” means that the gap along the entire length does not vary bymore than 10% of the average gap. An end dielectric 350 can bepositioned between the RF hot electrode 320 and the return electrode330. The end dielectric 350 can be any suitable material that canminimize electrical connection between the RF hot electrode 320 and thereturn electrode 330.

FIG. 12 shows another embodiment of the disclosure in which the RF hotelectrode 320 has a plurality of fingers 328 extending perpendicular toa major axis 308 of the housing 310. While the embodiment shown has fourfingers 328, those skilled in the art will understand that the RF hotelectrode 320 can have any suitable number of fingers 328 depending on,for example, the size of the housing 310. The return electrode 330 has ashape that is complementary to the RF hot electrode 320 so that there isa plurality of fingers 338 on the return electrode 330. In someembodiments, the return electrode 330 is shaped to maintainsubstantially the same gap between the RF hot electrode 320 and thereturn electrode 330. The wedge-shaped housing 310 shown in FIG. 12 hasa gap near the innermost finger 328 and the outermost finger 328 that islarger than the gap near the intermediate fingers. This variation may bedue to the shape of the housing 310 or to control the plasma density atthese regions.

Some embodiments include a cladding 360 adjacent a lower edge 329 of theRF hot electrode 320. Referring to FIG. 13, the RF hot electrode 320 isillustrated between two return electrodes 330. A cladding 360 separatesthe lower edge 329 of the RF hot electrode 320 from the substrate 60 andsusceptor assembly 140. The presence of the cladding 360, in someembodiments, help prevent or minimize sputtering of the RF hot electrode320 from contaminating the substrate 60. The cladding 360 can be made ofany suitable material including, but not limited to, dielectrics (e.g.,ceramic materials). The size of the cladding 360 can be adjusted to movethe lower edge 329 of the RF hot electrode 320 from the vicinity of thesubstrate 60. In some embodiments, the cladding 360 has a length Ls inthe range of about 10 mm to about 25 mm, or in the range of about 13 mmto about 20 mm or about 17 mm.

FIG. 14 shows another embodiment of the disclosure. The RF hotelectrodes 320 have a cladding 360 adjacent the lower edge 329. A returnelectrode 331 (e.g., ground or powered) is adjacent the cladding 360separating the spacer from the substrate 60 and susceptor assembly.Without being bound by any particular theory of operation, it isbelieved that the combination of the cladding 360 and return electrode331 minimizes direct interaction of the RF hot electrode 320 with thesubstrate. Although two RF hot electrodes 320 and two return electrodes330 are illustrated in FIG. 14, those skilled in the art will understandthat there can by any suitable number of RF hot electrodes 320 andreturn electrodes 330.

Referring to FIGS. 1, 2, 8 and 15, some embodiments of the disclosureare directed to processing chambers 100 including a susceptor assembly140 and a gas distribution assembly 120. FIG. 15 shows a cross-sectionalview of a processing chamber 100 in accordance with one or moreembodiments of the disclosure. The susceptor assembly 140 has a topsurface 141 to support and rotate a plurality of substrates 60 around acentral axis 161.

The gas distribution assembly 120 has a front surface 121 facing the topsurface 141 of the susceptor assembly 140 to direct a flow of gasestoward the top surface 141 of the susceptor assembly 140. The gasdistribution assembly 120 of some embodiments includes a plasma sourceassembly 300 with a wedge-shaped housing 310 (see FIGS. 10A to 12). Thewedge-shaped housing has an inner peripheral edge 123 and an outerperipheral edge 124 defining a major axis 308 of the housing 310. Thehousing 310 has a first side 371, a second side 372, a gas inlet 315 anda front face 312. A flow path is defined as the path followed by a gasflowing from the gas inlet 315 through the housing 310 and exiting fromthe front face 312.

The plasma source assembly 300 has at least one RF hot electrode 320with a first surface 322 oriented substantially parallel to the flowpath. At least one return electrode 330 is within the housing 310 andhas a first surface 332 oriented parallel to the flow path and spacedfrom the first surface 322 of the RF hot electrode 320 to form a gap340. The front face 312 of the wedge-shaped housing 310 of the plasmasource assembly 300 is positioned a distance from the top surface 141 ofthe susceptor assembly 140 in the range of about 1 mm to about 5 mm, orin the range of about 1.5 mm to about 4 mm, or about 2 mm. Theembodiment shown in FIG. 15 is merely exemplary of one possibleconfiguration of a processing chamber with a plasma source assembly andshould not be taken as limiting the scope of the disclosure.

Referring back to FIG. 6, some embodiments include a coaxial RF feedline 380 that passes through the housing 310 and provides power for theRF hot electrode 320 to generate the plasma in the gap 340. The coaxialRF feed line 380 includes an outer conductor 382 and an inner conductor384 separated by an insulator 386. The inner conductor 384 is inelectrical communication with the RF hot electrode 320 and outerconductor 382 is in electrical communication with electrical ground or adifferent phase power source (not shown) than the RF hot electrode. Asused in this specification and the appended claims, the term “electricalcommunication” means that the components are connected either directlyor through an intermediate component so that there is little electricalresistance. The gap between inner conductor 384 and outer conductor 382can be filled with a dielectric, which may be ceramic, but can be anysuitable dielectric material.

The coaxial RF feed line 380 may be constructed so that the outerconductor 382 terminates on the return electrode 330. The innerconductor 384 can terminate on the RF hot electrode 320. In someembodiments, the gas inlet 315 is fed to the housing around the outsideperiphery of the coaxial feed. The RF feed may be in the form of acoaxial transmission line. The outer conductor can beconnected/terminated in the return electrode, and the inner conductor isconnected to the RF hot electrode. The return electrode 330 can beconnected to the metal housing by any suitable method including, but notlimited to, a metal gasket. This helps to ensure a symmetric geometry ofthe return currents. All return currents flow up the outer conductor ofthe feed, minimizing RF noise. In some embodiments, the RF feed isdesigned to provide symmetric RF feed current to the RF hot electrode,and symmetric return currents. All return currents flow up the outerconductor, minimizing RF noise, and minimizing impact of sourceinstallation on operation.

For a linear radial plasma source, like that shown in FIGS. 6-8, in anyprocessing system that uses a rotating susceptor (platen), the plasmaexposure (treatment) is greater at the inner diameter (ID) of the wafercompared to the outer diameter (OD) of the wafer. In a system with acoaxial feed connected to the approximate center of the hot electrode,the difference between the ID and OD exposure can be about 2.7 times.Currently, the coaxial feed is connected to the hot electrode at aboutthe center of the electrode. This connection configuration may notprovide uniform plasma exposure at the ID and OD of the wafer. One ormore embodiments of the disclosure advantageously provide simple lineardesign plasma source. Some embodiments advantageously provide an innerdiameter feed at high frequency or very high frequency with increasingplasma flux from the wafer ID to OD.

Referring to FIGS. 15 and 16, the vertical plasma source (VPS) can be alinear plasma source with a powered electrode (hot electrode) and returnelectrode that extend from the ID to OD of the wafer and beyond. The gapbetween the hot electrode and return electrode can be substantiallyuniform along the length of the electrodes from the ID to OD.

The electrodes of some embodiments are enclosed by inner and outercladding made from a dielectric material to minimize metalcontamination. A gap is maintained between the bottom of the claddingand the wafer/susceptor that exposes plasma to the wafer.

Generally, the electric field (and plasma flux) generated in a plasmaassembly is greatest near the RF feed with field strength decreasingwith distance from the RF feed. In the linear vertical plasma source,the minimum electric field and plasma density occurs surprisinglyunderneath the RF feed. Without being bound by any particular theory ofoperation, it is believed that this is due to electromagnetic effectswhich increase with the frequency of the RF power. The inventors havefound that moving the RF feed toward the ID end of the hot electrode cancompensate for the exposure non-uniformity.

The power source 390 can be operated at any suitable frequency. It hasbeen found that higher frequency power may create a plasma densityvariation that can compensate for the differing exposure between the IDand OD due to susceptor rotation. In some embodiments, the power source390 is operated at high frequency (3-30 MHz) or at very high frequency(30-300 MHz). In some embodiments, the power source 390 is operated at60 MHz.

Referring to FIGS. 15 through 17, one or more embodiments of thedisclosure is directed to a plasma source assembly 300. The plasmasource assembly 300 includes a housing 310, shown in FIG. 17. Thehousing 310 of some embodiments holds or supports all of the componentsof the plasma source assembly except the power connection or gas lineconnections that might be used. Combined in one housing, the plasmasource assembly can be modular; allowing the assembly to be moved, addedto or removed from a processing apparatus. The housing 310 of someembodiments is wedge-shaped to fit into a gas distribution assembly 120like that shown in FIG. 4 or 5. While the housing 310 may bewedge-shaped, the shape of the plasma cavity or gap in which the plasmais formed, can be linear. The embodiment illustrated in FIG. 15 does notshow the housing for descriptive purposes.

FIG. 16 shows a partial cross-sectional side view of the plasma sourceassembly 300 of some embodiments. The housing 310 has an innerperipheral edge 123 and an outer peripheral end 124 that can be alignedwith the gas distribution assembly 120 illustrated in FIGS. 4 and 5. Asshown in FIG. 17, the housing 310 may include a gas inlet 315 to form aflow path 318 from the gas inlet 315 to allow a flow of gas to passthrough the housing 310 and out an opening 313 in the front face 312 ofthe plasma source assembly 300. The front face 312 can be formed by thehousing 310, the RF hot electrode 320, the return electrode 330, or anysuitable material that can be positioned a distance from the susceptorassembly. In some embodiments, the front face 312 is formed from acombination of separate components resulting in a mixture of materials.

The plasma source assembly includes an RF hot electrode 320 with anelongate body 321 that includes a first surface 322 and a second surface324 opposite the first surface 322. The first surface 322 and secondsurface 324 define the width of the RF hot electrode 320. In someembodiments, the first surface 322 and second surface 324 aresubstantially parallel. As used in this regard, the term substantiallyparallel means that the surfaces form major planes that are within ±10°,±9°, ±8°, ±7°, ±6°, ±5°, ±4°, ±3°, ±2° or ±1° of being parallel. In someembodiments, the width of the RF hot electrode 320 is in the range ofabout 2 mm to about 20 mm, or in the range of about 3 mm to about 15 mm,or in the range of about 4 mm to about 10 mm, or in the range of about 5mm to about 9 mm, or in the range of about 6 mm to about 8 mm, or about7 mm.

The elongate body 321 of the RF hot electrode 320 has an innerperipheral end 323 and an outer peripheral end 325. The inner peripheralend 323 of the RF hot electrode 320 is positioned within the housing 310near the inner peripheral edge 123 of the housing 310. The outerperipheral edge 325 of the RF hot electrode 320 is positioned within thehousing 310 near the outer peripheral edge 124 of the housing 310. Theinner peripheral end 323 and outer peripheral end 325 define a length Lof the RF hot electrode 320. The embodiment illustrated in FIG. 16 showsthe housing 310 having about the same length as the RF hot electrode320. This is merely representative of one possible configuration andshould not be taken as limiting the scope of the disclosure. The housingof some embodiments extends beyond the ends of the RF hot electrode andmay wrap around at least some of the RF hot electrode. The length L ofthe RF hot electrode 320 of some embodiments is in the range of about160 mm to about 440 mm. The length L of the RF hot electrode 320 can beconfigured to span the width of a substrate to be processed. Forexample, if the substrates being processed are 200 mm diameter wafers,the RF hot electrode can have a length L in the range of about 160 mm toabout 440 mm, or in the range of about 180 mm to about 220 mm, or in therange of about 190 mm to about 210 mm, or in the range of about 195 mmto about 205 mm. If the substrates being processed are 300 mm diameterwafers, the RF hot electrode can have a length L in the range of about160 mm to about 440 mm, or in the range of about 260 mm to about 440 mm,or in the range of about 280 mm to about 320 mm, or in the range ofabout 290 mm to about 310 mm, or in the range of about 295 mm to about305 mm.

A return electrode 330 can be any component that is suitable to allow areturn current to flow or provide an opposite polarity voltage from theRF hot electrode. The term “return electrode” is used to represent anelectrical connection that forms a complete circuit with the RF hotelectrode and should not be taken as implying a direction for a flow ofcurrent or electrons. The return electrode 330 of some embodiments isthe housing 310. In some embodiments, the return electrode 330 is aseparate component within the housing 310. The return electrode 330 canbe made from the same material as the housing 310 but be electricallyisolated from the housing 310, or the return electrode 330 can be madefrom a different material than the housing 310. In the embodimentsillustrated, the return electrode 330 is a different material than thehousing 310. The return electrode 330 of some embodiments has anelongate body that extends from the inner peripheral edge to the outerperipheral edge of the housing. The return electrode is spaced from theRF hot electrode 320 to provide a gap 340 in which a plasma can form.

An RF feed 380 connects a power source 390 to the RF hot electrode 320.The RF feed 380 can be a coaxial RF feed line, like that shown in FIG.6. As illustrated in FIG. 16, the RF feed 380 connects to the RF hotelectrode at a distance D_(e) from the inner peripheral edge 323 of theRF hot electrode 320. The distance D_(e) of some embodiments is lessthan or equal to about 25% of the length L of the RF hot electrode 320.In some embodiments, the distance D_(e) is less than or equal to about20%, 15%, 10%, 5%, 4%, 3%, 2% or 1% of the length L of the RF hotelectrode 320.

As illustrated in FIG. 17, in some embodiments the RF hot electrode 320has RF hot electrode cladding 360 positioned so that the RF hotelectrode 320 is not exposed directly to the substrate or susceptorassembly. As used in this manner, the term “not exposed directly” andthe like means that an atom ejected from the RF hot electrode 320 cannottravel a straight path to impact the surface of the substrate. In theembodiment shown, the RF hot electrode cladding 360 wraps around allexposed sides and surfaces of the RF hot electrode 320. The RF hotelectrode cladding 360 of some embodiments comprises one or more ofsilicon or silicon oxide. In some embodiments, the RF hot electrodecladding 360 comprises or consists essentially of quartz. In someembodiments, the RF hot electrode cladding 360 is made from a materialthat is not sputtered as a contaminant on a wafer being processed. TheRF hot electrode cladding 360 material may depend on the process ordeposition being performed.

In some embodiments, the return electrode 330 includes a returnelectrode cladding 361. The return electrode cladding 361 of someembodiments is positioned so that the return electrode 330 is notdirectly exposed to the substrate or susceptor surface. In someembodiments, the return electrode cladding 361 comprises one or more ofsilicon, silicon oxide or aluminum oxide.

The return electrode cladding 361 of some embodiments comprises amaterial that is different from the RF hot electrode cladding 360. Insome embodiments, the RF hot electrode cladding 360 and the returnelectrode cladding 361 are made from the same material. In someembodiments, the RF hot electrode cladding 360 comprises quartz and thereturn electrode cladding comprises aluminum oxide. In some embodiments,the RF hot electrode cladding 360 consists essentially of quartz and/orthe return electrode cladding consists essentially of quartz or aluminumoxide. As used in this manner, the term “consists essentially of” meansthat the composition of the subject cladding is greater than or equal toabout 95%, 98% or 99% of the stated material on a weight basis.

The RF hot electrode cladding 360 and return electrode cladding 361 canform the front face 312 of the plasma source assembly 300. The distanceG_(h) from the RF hot electrode cladding 360 to the substrate 60 can bethe same as or different from the distance G_(r) from the returnelectrode cladding 361 to the substrate 60.

The plasma source assembly 300 of some embodiments provides a plasmawith an ion flux generated at the inner peripheral end 323 of the RF hotelectrode 320 that is less than an ion flux generated at the outerperipheral end 325 of the RF hot electrode 320.

Additional embodiments of the disclosure are directed to methods ofprocessing a substrate. A substrate 60 is positioned on a susceptorassembly 140 adjacent a gas distribution assembly 120. The gasdistribution assembly 120 includes a plasma source assembly inaccordance with one or more embodiments of the disclosure. A gas isflowed through the gas inlet 315 of the housing 310 into the gap 340between the RF hot electrode 320 and the return electrode 330. The RFhot electrode 320 is energized through the RF feed 380 positioned within25% of the length L of the RF hot electrode 320 measured from the innerperipheral end 323 to form a plasma in the gap 340. The plasma flows outthe front face 312 of the housing 310 to expose the substrate 60 to theplasma.

An argon plasma was generated at 100 W, 60 MHz with a pressure of 6.5 T.The RF feed was located within 5% of the length of the RF hot electrodemeasured from the end of the inner peripheral end of the electrode. Theplasma density, ion flux and etch rate was observed to increase from thewafer ID to the wafer OD.

Argon plasma ion flux was measured at different power settings. Theintegrated ion flux to the wafer, as illustrated in FIG. 18, showed thatthe ion flux increased from the wafer ID to wafer OD.

ALD silicon dioxide films were deposited using the ID feed/VPS plasmasource at 60 MHz, 400° C., 300 W and 6.5 Torr. The SiO2 within-waferuniformity was less than 2%. The wet etch rate ratio (WERR) comprised toa thermal SiO2 deposition in dilute HF (1:100) was about 1.9.

ALD silicon nitride films were deposited using ID feed/VPS plasma sourceat 60 MHz, 500° C., 100 W and 6.5 Torr. The SiN within-wafer uniformitywas less than 2% and the wet etch rate in dilute HF was about 4.5 Å/min.

Some embodiments of the disclosure are directed to processing chamberscomprising at least one capacitively coupled plasma source positionedalong an arcuate path in a processing chamber. As used in thisspecification and the appended claims, the term “arcuate path” means anypath which travels at least a portion of a circular-shaped or anoval-shaped path. The arcuate path can include the movement of thesubstrate along a portion of the path of at least about 5°, 10°, 15°,20°, 30°, 45° or 60°.

Additional embodiments of the disclosure are directed to methods ofprocessing a plurality of substrates. The plurality of substrates isloaded onto substrate support in a processing chamber. The substratesupport is rotated to pass each of the plurality of substrates across agas distribution assembly to deposit a film on the substrate. Thesubstrate support is rotated to move the substrates to a plasma regionadjacent a capacitively coupled plasma source generating substantiallyuniform plasma exposure in the plasma region. This is repeated until afilm of predetermined thickness is formed.

Rotation of the carousel can be continuous or discontinuous. Incontinuous processing, the wafers are constantly rotating so that theyare exposed to each of the injectors in turn. In discontinuousprocessing, the wafers can be moved to the injector region and stopped,and then to the region between the injectors and stopped. For example,the carousel can rotate so that the wafers move from an inter-injectorregion across the injector (or stop adjacent the injector) and on to thenext inter-injector region where the carousel can pause again. Pausingbetween the injectors may provide time for additional processing betweeneach layer deposition (e.g., exposure to plasma).

The frequency of the plasma may be tuned depending on the specificreactive species being used. Suitable frequencies include, but are notlimited to, 400 kHz, 2 MHz, 13.56 MHz, 27 MHz, 40 MHz, 60 MHz, 100 MHz,121 MHz and 162 MHz.

According to one or more embodiments, the substrate is subjected toprocessing prior to and/or after forming the layer. This processing canbe performed in the same chamber or in one or more separate processingchambers. In some embodiments, the substrate is moved from the firstchamber to a separate, second chamber for further processing. Thesubstrate can be moved directly from the first chamber to the separateprocessing chamber, or the substrate can be moved from the first chamberto one or more transfer chambers, and then moved to the separateprocessing chamber. Accordingly, the processing apparatus may comprisemultiple chambers in communication with a transfer station. An apparatusof this sort may be referred to as a “cluster tool” or “clusteredsystem”, and the like.

Generally, a cluster tool is a modular system comprising multiplechambers which perform various functions including substratecenter-finding and orientation, degassing, annealing, deposition and/oretching. According to one or more embodiments, a cluster tool includesat least a first chamber and a central transfer chamber. The centraltransfer chamber may house a robot that can shuttle substrates betweenand among processing chambers and load lock chambers. The transferchamber is typically maintained at a vacuum condition and provides anintermediate stage for shuttling substrates from one chamber to anotherand/or to a load lock chamber positioned at a front end of the clustertool. Two well-known cluster tools which may be adapted for the presentdisclosure are the Centura and the Endura both available from AppliedMaterials, Inc., of Santa Clara, Calif. However, the exact arrangementand combination of chambers may be altered for purposes of performingspecific steps of a process as described herein. Other processingchambers which may be used include, but are not limited to, cyclicallayer deposition (CLD), atomic layer deposition (ALD), chemical vapordeposition (CVD), physical vapor deposition (PVD), etch, pre-clean,chemical clean, thermal treatment such as RTP, plasma nitridation,degas, orientation, hydroxylation and other substrate processes. Bycarrying out processes in a chamber on a cluster tool, surfacecontamination of the substrate with atmospheric impurities can beavoided without oxidation prior to depositing a subsequent film.

According to one or more embodiments, the substrate is continuouslyunder vacuum or “load lock” conditions, and is not exposed to ambientair when being moved from one chamber to the next. The transfer chambersare thus under vacuum and are “pumped down” under vacuum pressure. Inertgases may be present in the processing chambers or the transferchambers. In some embodiments, an inert gas is used as a purge gas toremove some or all of the reactants after forming the layer on thesurface of the substrate. According to one or more embodiments, a purgegas is injected at the exit of the deposition chamber to preventreactants from moving from the deposition chamber to the transferchamber and/or additional processing chamber. Thus, the flow of inertgas forms a curtain at the exit of the chamber.

During processing, the substrate can be heated or cooled. Such heatingor cooling can be accomplished by any suitable means including, but notlimited to, changing the temperature of the substrate support (e.g.,susceptor) and flowing heated or cooled gases to the substrate surface.In some embodiments, the substrate support includes a heater/coolerwhich can be controlled to change the substrate temperatureconductively. In one or more embodiments, the gases (either reactivegases or inert gases) being employed are heated or cooled to locallychange the substrate temperature. In some embodiments, a heater/cooleris positioned within the chamber adjacent the substrate surface toconvectively change the substrate temperature.

The substrate can also be stationary or rotated during processing. Arotating substrate can be rotated continuously or in discrete steps. Forexample, a substrate may be rotated throughout the entire process, orthe substrate can be rotated by a small amount between exposures todifferent reactive or purge gases. Rotating the substrate duringprocessing (either continuously or in steps) may help produce a moreuniform deposition or etch by minimizing the effect of, for example,local variability in gas flow geometries.

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments of the disclosure may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

What is claimed is:
 1. A plasma source assembly comprising: a housinghaving an inner peripheral edge, an outer peripheral edge and a frontface, the housing including a gas inlet to form a flow path from the gasinlet to allow a flow of gas to pass through the housing and out anopening in the front face; an RF hot electrode within the housing, theRF hot electrode having an elongate body with an inner peripheral endnear the inner peripheral edge of the housing and an outer peripheralend near the outer peripheral edge of the housing and defining a lengthof the RF hot electrode; a return electrode having an elongate bodyextending between the inner peripheral edge and the outer peripheraledge of the housing, the return electrode spaced from the RF hotelectrode to provide a gap in which a plasma can form; and an RF feedconnected to the RF hot electrode at a distance from the innerperipheral end of the RF hot electrode that is less than or equal toabout 25% of the length of the RF hot electrode.
 2. The plasma sourceassembly of claim 1, wherein the return electrode is the housing.
 3. Theplasma source assembly of claim 1, wherein the RF feed is connected tothe RF hot electrode at a distance from the inner peripheral end of theRF hot electrode that is less than or equal to about 5% of the length ofthe RF hot electrode.
 4. The plasma source assembly of claim 1, furthercomprising a RF hot electrode cladding positioned so that the RF hotelectrode is not exposed.
 5. The plasma source assembly of claim 4,wherein the RF hot electrode cladding comprises one or more of siliconor silicon oxide.
 6. The plasma source assembly of claim 4, wherein theRF hot electrode cladding comprises a material that is not sputtered asa contaminant on a wafer being processed.
 7. The plasma source assemblyof claim 4, further comprising a return electrode cladding positioned sothat the return electrode is not exposed.
 8. The plasma source assemblyof claim 7, wherein the return electrode cladding is a differentmaterial than the RF hot electrode cladding.
 9. The plasma sourceassembly of claim 7, wherein the return electrode cladding comprises oneor more of silicon, silicon oxide or aluminum oxide.
 10. The plasmasource assembly of claim 1, wherein an ion flux generated at the innerperipheral end of the RF hot electrode is less than an ion fluxgenerated at the outer peripheral end of the RF hot electrode.
 11. Theplasma source assembly of claim 1, wherein the gap between the RF hotelectrode and the return electrode has a width in the range of about 4mm to about 15 mm.
 12. The plasma source assembly of claim 1, whereinthere are two return electrodes with one return electrode on each sideof the RF hot electrodes, each return electrode spaced from the RF hotelectrode to form a gap.
 13. The plasma source assembly of claim 12,wherein each of the gaps between the RF hot electrode and the returnelectrode have about the same width.
 14. A processing chambercomprising: a susceptor assembly within the processing chamber, thesusceptor assembly having a top surface to support and rotate aplurality of substrates around a central axis; and a gas distributionassembly having a front surface facing the top surface of the susceptorassembly to direct a flow of gases toward the top surface of thesusceptor assembly, the gas distribution assembly including a plasmasource assembly comprising a housing having an inner peripheral edge, anouter peripheral edge and a front face, the housing including a gasinlet to form a flow path from the gas inlet to allow a flow of gas topass through the housing and out an opening in the front face, an RF hotelectrode within the housing, the RF hot electrode having an elongatebody with a first surface and a second surface, an inner peripheral endnear the inner peripheral edge of the housing and an outer peripheralend near the outer peripheral edge of the housing and defining a lengthof the RF hot electrode, a first return electrode within the housing,the return electrode having an elongate body extending between the innerperipheral edge and the outer peripheral edge of the housing, the firstreturn electrode spaced from the first surface of the RF hot electrodeto provide a first gap in which a plasma can form, a second returnelectrode within the housing, the second return electrode having anelongate body extending between the inner peripheral edge and the outerperipheral edge of the housing, the second return electrode spaced fromthe second surface of the RF hot electrode to provide a second gap inwhich a plasma can form, and an RF feed connected to the RF hotelectrode at a distance from the inner peripheral end of the RF hotelectrode that is less or equal to about 25% of the length of the RF hotelectrode, wherein the front face of the housing of the plasma sourceassembly is positioned a distance from the top surface of the susceptorassembly in the range of about 1 mm to about 5 mm, and an ion fluxgenerated at the inner peripheral end of the RF hot electrode is lessthan an ion flux generated at the outer peripheral end of the RF hotelectrode.
 15. The processing chamber of claim 14, wherein the RF feedis connected to the RF hot electrode at a distance from the innerperipheral end of the RF hot electrode that is less than or equal toabout 5% of the length of the RF hot electrode.
 16. The processingchamber of claim 14, further comprising a RF hot electrode claddingpositioned so that the RF hot electrode is not exposed directly to thesusceptor assembly.
 17. The processing chamber of claim 16, wherein theRF hot electrode cladding comprises one or more of silicon or siliconoxide.
 18. The processing chamber of claim 16, further comprising areturn electrode cladding positioned so that the first return electrodeand second return electrode are not exposed directly to the susceptorassembly.
 19. The processing chamber of claim 18, wherein the returnelectrode cladding comprises one or more of silicon, silicon oxide oraluminum oxide.
 20. A method of processing a substrate, the methodcomprising: positioning a substrate on a susceptor assembly adjacent agas distribution assembly, the gas distribution assembly including aplasma source assembly comprising a housing having an inner peripheraledge, an outer peripheral edge and a front face, the housing including agas inlet to form a flow path from the gas inlet to allow a flow of gasto pass through the housing and out an opening in the front face, an RFhot electrode within the housing, the RF hot electrode having anelongate body with a first surface and a second surface, an innerperipheral end near the inner peripheral edge of the housing and anouter peripheral end near the outer peripheral edge of the housing anddefining a length of the RF hot electrode, a first return electrodewithin the housing, the return electrode having an elongate bodyextending between the inner peripheral edge and the outer peripheraledge of the housing, the first return electrode spaced from the firstsurface of the RF hot electrode to provide a first gap in which a plasmacan form, a second return electrode within the housing, the secondreturn electrode having an elongate body extending between the innerperipheral edge and the outer peripheral edge of the housing, the secondreturn electrode spaced from the second surface of the RF hot electrodeto provide a second gap in which a plasma can form, and an RF feedconnected to the RF hot electrode at a distance from the innerperipheral end of the RF hot electrode that is less or equal to about25% of the length of the RF hot electrode; flowing a gas through the gasinlet of the housing into the first gap between the RF hot electrode andthe first return electrode and the second gap between the RF hotelectrode and the second return electrode; energizing the RF hotelectrode to form a plasma in the first gap and the second gap, theplasma having an ion flux generated at the inner peripheral end of theRF hot electrode that is less than an ion flux generated at the outerperipheral end of the RF hot electrode; and exposing the substrate tothe plasma.